Photographic elements and process of preparing the same



Dec. 28, 1954 w, SANER 2,698,241

PHOTOGRAPHIC ELEMENTS AND PROCESS OF PREPARING THE SAME Filed June 7, 1952 Water-permeable colloid (e.g. gelatin) and silver halide Mixture of(a)polyester of ethylene glycol, terephthallc acid and polyethylene glycol or saturated aliphatic dicarboxylic acid, soluble in CH CI=CCl and (b)organic polyisocyanate or polyisothiocyanate Polyethylene terephthalate base Polyethylene terephthalate base I INVENTOR WILLIA M RUSSELL SANER ATTORNEY United States Patent PHOTOGRAPHIC ELEMENTS AND PRGGESS F PREPARENG THE SAME William Russeii Saner, Piainfield, N. J.,-:assignor to E. I. do Pontde Ncmonrsand-Company, WiImingtom'DeL, a corporation (if-Delaware Application June 7, 1952, Serial No. 292,387

13 Qlaims. (Cl.'95-9) This invention 'is concerned withphotographic iilms Which have a unique substratum. 'More particularly 'it is concerned with photographicfilms which have a hydrophobic film base, a substratumcomposed ofa mixture ple andeffective and provide firmv anchorage ofa colloid .silver halide emulsion to a hydrophobic film'base both While under wet and dry conditions. stilllfurther-object is to provide such anchorage when the'base'is composed of a polyethylene terephthalate.

It has been determined that a colloid silver'halide emulsion layer can be firmly anchored to a hydrophobic orientable polyester film'base by'first applying to the sur- :face or surfaces of thefilmbasea solution oframixture of (1) a polyester of a glycol and terephthalic acid which has amolecular weight in excess of 5,000 and is soluble to the extent of atleast /2 by weight in trichlorethylene and (2) anorganic polyisocyanate or an organic -polyisothiocyanate including diisocyanate dimers. Com- =ponent (2) may be presentin anamount constituting from 1% to 50% by weight of the solid materials-pres- 'ent in the coating solution.

The mixture of the polyester and polyisocyflnate or polyisothiocyanate can be applied to the'orienta'blepoiyester base from about /z% to 25% or'moreby'weight solution in a'suitable non-reactive solvent such as chlorinated hydrocarbon. The solvents should be'volatile and preferred solvents are, methylene chloride, t'riChlorethylene, carbon tetrachloride, etc. Afterthe'layerhasdried a thin substratum of a water-permeablecolloidis applied andthen a water-permeable colloid silver halide emulsion layer is applied. However, while it ispreferableto apply the water-permeable colloid substratum item 'be eliminated. if desired because a colloid silver halideemulsion layer strongly adheres to the layercomposed of the mixture of the polyester and the polyiso'cyanate or polyisothiocyanate compound. The water-permeablecolloid may be gelatin, polyvinyl alcohol, a partiallyhydrolyzeldj p0lyvinyl acetace or chloracetate, apolyvinyl. acetalor a-cellulose derivative, all of hydrophilic character.

Polyesters suitable for use'in the mixturesofthessnblayer that have a substantial solubility in trichlorethylene can be made by condensing a mixture of (-1-) a -poly- 'methylene glycol havingfrom 2 to l0 methylen'e groups and (2) a polyethyleneglycol containing" from'l to 5 'oxyethylene radicals with terephthalic't acid oran acid r chloride oracid bromide thereof, ora diester thereof with an alkanol of 1 to 6 carbon :atoms. Thexmol-percent of polyethylene glycol in the polymethylenezglycol/polyethylene glycol mixture may vary from 20% to 100%, with a preferred range of -25 'to 75%.

Another group of suitable.polyesters are those.obtainable by condensing a polymethylene glycolLliavin'gLZ; to"10 methylene groups with a mixture of (1-) .tereph'thalic acid or'an acid 'chloride'or acidibromide' thereof, or a diester thereof withan' alkanol of'1'to6 carbon' fatoms and (2) a saturated aliphatic *dicarboxylic'acidof 4 to 16 carbon atoms or an acid chloride or anacidbromide 2,698,241 Patented Dec. 28,1954

:thereof, or a diester thereof with anlalkanolzof 1 to :6 carbon atoms. Preferred aliphatic :dicarboxylic"acid compoundsare adipic,'sebaciciacid and azelaic acid' and :their .acid .chlorides and bromides, and their dimethyl and diethyl esters. The polyesterificationreactioncan :takeplacein the same manner described in:the preceding paragraph.

in the case of the second specific group ,of polyesters :andpolymethylene glycol should be in excess and'the terephthalic acid compound should constitute at least 25% of the total acid compound, and the aliphaticdicarboxylic acid compound may'cons'titute from 10% to 75% of the total acid compound. 'In addition to these two compounds'there may alsobe' present from 1% to 25% of another dicar'boxylic acid compound which is capable offorming a polyester by a condensation reaction. Among suchlatter useful compounds are bibenzoic acid, phthalic acid, isophthalic acid and their dimethyl and 'diethyl esters.

.Film elements of the types describedabove areshown in the accompanying drawing, which constitutes .a part of :this .sp ecification: and wherein :Fig. l is a schematic cross-sectional view of one type of film element of the invention, and

Fig. 2 is a schematic cross-sectional view of another type of .film element of-the invention.

.Referringnowto Fig. l of thedrawing apolyethylene Lterephthalate film base 1 .is provided .with'a layer 20f a mixtureofapolyester of ethylene glycoLterephthalic acid, and a saturated aliphatic dicarboxylic acid, said polyester being. soluble intrichloroethylene and thislayer carries a water-permeable-colloid silver halide emulsion layer 3.

In Fig-2.the'film element is like that described in' Fig. '1 except that a sublayer 3 composed of a water-permea- .blecolloid, e. g., gelatin is interposed between the'layer 2-and silver halide emulsion layer 3.

There are many'known organic polyisocyanates and polyisothiocyana'tes which can be used in practicing this invention. These compounds contain two or more -N=C=Y groups where Y is 0 or S. The more readily available compounds contain two TN=C='Z ,groups where Z is a chalcogen of atomic weight less thari'3'3. While:the. compounds-having a hydrocarbon radical attached to the N=C=Y groups are preferred the-diisocyanate dimers which contain a uretidinedione or 1,3- oxazetidene ring have utility. Suitable compounds of this type are described in Kirkpatrick and WilletU. S.

application Ser. No. 261,922, filed December'l'S, 1951.

While the invention is useful with any cold-drawing, orientable'polyester including those described in Carothers U. S. Patents 2,216,736 and 2,071,250, it is particularly applicable to a hydrophobic film base composed of a high-melting difiicultly soluble, usually microcrystalline, cold-drawing linear, highly polymerized esters of terephthalic acid and glycols of the series HO(CH2)1iOI-I where n isan'integer with the range of 2 to 10, described inWhinfield et'al." U. S. P.'2,465,-319.

Anyofthe conventional coating methods can be used for applying the layer of the mixture of the solvent-soluble polyester and the poiyisocyanate or polyisothiocyanate to the surface of the film support, e. g.,.coating from a hop- -per,. skim coating where the surface ofthe filnrpa sses un'der azrollerand contactswiththe'surface of the liquid, coating with applicator or transfer rolls, spray coating, etc.

"'Do'ctorblades, air doctor blades, etc., can be used to remove excess'liquid. After the sublayerhas been applied to one or both surfaces of the sheet of film th'e sublayer is dried by heating it to a temperature of 50 C. or less to C. or more. A current of air can be passed over the coated surface during this'drying operation.

'The' invention will be further illustratedbub is-notin- 'tended to'belimite'd by the following examples'wherein the parts and percentages stated'areby weight.

Example I A polyester was preparedbyheating dimethyl terephthalate with a stoichiometrical excess of diethylene glycol .at.170.220 C,. in the presence of- 003% byweight oflitharge based on-the-dimethyl terephthalate untilevolut-ion.of methanol ceased. The temperature Wasthen increased to 250 to 280 C., and the pressure reduced to 0.1 to 0.5 mm. of mercury. Diethylene glycol was evolved as polymerization proceeded. The resulting polyester, after cooling to room temperature, was clear, soft and flexible and had an intrinsic viscosity of 0.64 in a 40/60 by volume phenol-tetrachloroethane mixture.

A 4% solution in methylene chloride of the polyester so obtained, containing 25% by weight of methylene bis (4-phenylisocyanate) (based on the polyester) was applied to a sample of biaxially stretched polyethylene terephthalate film base having a thickness of 4 mils. After drying, a layer of gelatin was applied to the polyester/diisocyanate surface from the following dispersion:

Per cent Gelatin 1 Acetic acid 4 Methanol 40 Acetone 55 The film was dried for 5 minutes at 100 C. and coated with a gelatino-silver iodobromide emulsion containing 4.9% of silver halide comprised of 98.44% silver bromide and 1.56% silver iodide, dispersed in gelatin (6.2% by weight of the total emulsion). After drying, the adhesion of the emulsion layer to the film base was good. The film having this gelatino-silver halide layer was developed for 5 minutes at 70 F. in the following solution:

Grams N-methyl p-aminophenol sulfate Hydroquinone Sodium sulfite Potassium carbonate 104.3 Sodium hydroxide 6.6 Potassium bromide 11.7 Water to make 4 liters.

, The developed film was rinsed in water for 5 minutes and immersed for minutes at 70 F. in a fixing bath of the following composition:

Grams Sodium thiosulfate 350 Sodium sulfite Sodium acetate 18 Potassium aluminum sulfate 32 Citric acid 8.0 Water to make 1 liter.

The film was washed in water for 10 minutes and found to have good wet anchorage.

Example II A photographic film was prepared, exposed and processed as in Example 1, except that a polyester prepared by reacting dimethyl terephthalate and adipic acid in equal molar quantities with ethylene glycol, was substituted for the polyester of Example 1.

Example III Example IV A photographic film was prepared, exposed and processed as in Example I, except that a polyester prepared by reacting dimethyl terephthalate and sebacic acid in equal molar quantities with ethylene glycol was substituted for the polyester of Example I. The wet and dry anchorages were similar.

Example V A photographic film was prepared, exposed and processed as in Example I, except that a polyester prepared by reacting dimethyl terephthalate, dimethyl bibenzoate, and azelaic acid (40/20/40 mole percent) with ethylene glycol was substituted for the polyester of Example I. The wet and dry anchorages were similar.

Example VI A photographic film was prepared, exposed and processed as in Example I, except that a polyester, prepared by reacting dimethyl terephthalate, dimethyl isophthalate and sebacic acid (50/25/25 mole percent) with ethylene glycol, was substituted for the polyester of Example I.

Results were similar.

Example VII The entire procedure of Example II was repeated, except that the film base was not biaxially stretched. The wet and dry anchorages were good.

Example VIII Example II was repeated except that no gelatin sublayer was applied to the base, the gelatino-silver halide layer being applied to the base directly. The wet and dry anchorages were adequate but not quite as good as in Example I.

Example IX Example II was repeated except that toluene-2,4-diisocyanate was substituted for methylene bis (4-phenylisocyanate) and similar anchorage results were obtained.

Example X Example II was repeated except that the dimer of toluene-2,4-diisocyanate was substituted for methylene bis (4-phenylisocyanate) and similar anchorage results were obtained.

Example XI A 4% solution in methylene chloride of the polyester of Example II, containing 25% methylene bis (4-phenylisocyanate), based on the polyester, was applied to biaxially stretched polyethylene terephthalate film. After drying, a layer of meta-(benzoylacetamido)-benzaldehyde-sodium-o-sulfobenzaldehyde polyvinyl mixed acetal described in McQueen U. S. Patent 2,513,190 having the following composition was applied:

The film was dried at 50 C. and heated at C. for two minutes and coated with a polyvinyl acetal color former silver halide dispersion containing 1.5% by weight of silver iodobromide, comprised of approximately 1.3% silver iodide and 98.7% silver bromide, dispersed in the polymeric color-former (3.8% by weight of the total emulsion) described in U. S. Patent 2,513,190. After drying at 75 F. the emulsion was found to have good adherence to the film base. It was exposed and processed in the following solutions:

(1) Developerfor 10 minutes at 68 F. Grams p-Aminodiethylaniline hydrochloride 2.5 Sodium sulfite 10.0 Sodium carbonate 46.8 Potassium bromide 2.0 Water to make 1 liter.

(2) Water rinsefor 30 seconds.

(3) Fixerfor 5 minutes at 68 F.

Sodium thiosulfate grams 240.0 Sodium sulfite do 15.0 Sodium tetraborate do. 18.0 Glacial acetic acid cc 12.0 Potassium aluminum sulfate grams 20.0 Water to make 3 liters.

(4) Water rinsefor 5 minutes.

(5) Bleach for 5 minutes at 68 F. Grams Potassium ferricyanide 100.0 Boric acid 10.0 Sodium tetraborate 5.0

Water to make 1 liter.

(6) Water rinse-for 5 minutes.

(7) Fixer-40r- 5 minutes at 68 F;

"Sodium thiosulfate a ..;grams 200.0

Water to make l literi (8) Water rinsefor' minutes.

The inventiomas stated above, is not limited to the specific polyisocyanates or polyisothiocyanates-, given in the examples. Many useful compounds are; known. Exemplary compounds include polymethylene diisocyanates and diisothiocyanates such as ethylene diisocyanate, trimethylene diisocyanate, -dodecamethylene diisocyanate, hexamethylene diisocyanate, tetrame'thylene diisocyanate, pentamethylenediisocyanate, and the corresponding diisothiocyanates; alk-y-lene diisocyanates and diisothiocyanate such as propylene-1-,2-diisocyanate, 2,3-dim'e'thyltetra methylene diisocyanate and-diisothi'o'cyanate, butylene-l,2- diisocyanate, butylene-1,3-diisothiocyanate, and butylene- 1,3-diisocyanate; alkylidene diisocyanates and diisothiocyanates such as ethylidene diisocyanate (CH3CH(N CO)2) and heptylidene diisothiocyanate (CH3(CH2)5CH(CNS)2); cycloalkylene diisocyanates and diisothiocyanates such as 1,4 diisocyanatocyclohexane, cyclopentylene 1,3 diisocyanate, and cyclohexylene-1,2-diisothiocyanate; aromatic polyisocyanates and polyisothiocyanates such as m-phenylene diisothiocyanate, p-phenylene diisocyanate, p-phenylone diisothiocyanate, 1-methyl-phenylene-2,4-diisocyanate, naphthylene-1,4-diisocyanate, o,o'-toluene diisocyanate, diphenyl-4,4-diisothiocyanate and diisocyanate, benzenel,2,4-triisothiocyanate, 5-nitro-1,3-phenylene diisocyanate, xylylene-l,4-diisocyanate, xylylene-l,3-diisocyanate, 4,4- diphenylenemethane diisocyanate, 4,4- diphenylenepropane diisocyanate and xylylene-l,4 diisothiocyanate; aliphatic-aromatic diisocyanates and diisothiocyanates such as phenylethylene diisocyanate (C5HeCl-I(NCO)CH2NCO); diisocyanates and diisothiocyanates containing heteroatoms such as SCNCHzOCI-IzNSC, SCNCHzCHzOCI-IaCHaNSC and SCN(CH2)3S(CH2)3NSC: 1,2,3,4-tetraisocyanatobutane, butane-1,2,2-triisocyanate, l-isocyanato, 4-isothiocyanatohexane, and 2 chloro 1,3 diisocyanatopropane. Mixtures of two or more of such compounds can be used.

Suitable diisocyanate dimers are described in Kirkpatrick and Willett, U. S. application Ser. No. 261,922, filed December 15, 1951. These compounds are more reactive when the coated film is heated to an elevated temperature, e. g., 150 C.

The preferred diisocyanates, diisothiocyanates and mixed isocyanate-isothiocyanates have the general formula ZCNRNCZ in which R is a divalent hydrocarbon radical and Z is a chalcogen of atomic weight less than 33.

In place of the specific colloid silver-halide emulsions described in the foregoing examples there may be coated onto the layer of isocyanate compound various other colloid silver halide emulsion layers and water-permeable colloid sublayers free from light-sensitive silver-halides. Thus among the additional colloids which can be anchored in accordance with the invention are polyvinyl alcohols and water-soluble polyvinyl alcohol derivatives in general, e. g., partially hydrolyzed polyvinyl acetates, and mixed polyvinyl-chloride-acetates, hydrolyzed interpolymers of vinyl acetate with unsaturated compounds, for example, maleic anhydride, acrylic acid esters, etc. Suitable colloids of the last mentioned types are disclosed in United States Patents 2,276,322, 2,276,323 and 2,397,866. Still other colloids include hydrophilic partially substituted polyvinyl esters and acetals and the low substituted cellulose esters of saturated aliphatic monocarboxylic acids of 2 to 4 carbon atoms and low substituted cellulose ethers, e. g., methyl-cellulose, ethyl-cellulose, etc. Additional natural colloids include casein, albumin, gum arabic, agar agar, polyglycuronic acid, etc., which are also anchored to supports by these new substrata.

In the case of color films for multicolor photography three diiferentially sensitized colloid silver halide emulsion layers containing color formers or using colloid color formers as the binding agent for the silver halide grains can be used. These layers should be so arranged and sensitized that they record light of a difierent color of the visible spectrum. The color formers thus can be selected to yield yellow, blue-green (cyan) and magenta quinoneimine, azomethine, etc., dyes in the appropriate layers as is common in the art and described in Jennings 2,397,864 and other patents. Filter dyes may be present in one or more of the above color former layers or in a separate 6 stratum, e. g., a polyvinyl alcohol'or' equivalent hyd'roxyl polymer layer as described above. In general, aiyellow filter dye is used in a stratum above the two lightesensitive layers most .distantfrom the camera side 'of the filmt- The sublayers' can be used black:-and= white=film as well as colorfilm for motion picture and stilllphoto'g raphy, portrait film, document recording film, lithographic and industrial andmedicalX-ray film, etc.

An advantage of this-inventionis that itFprOVidesa-simple and economical methodof subbing film base; Another advantage is that the films have; good and adequatean: chorage between thefilm base and a colloid silver halide emulsion layer. This advantage is of special importance with regard to films having a polyethylene terephthalate base. A further advantage is that the anchorage is equally good' whether the mixture is applied to-oriented or nom oriented. film. Still' other advantages 'will be 'apparent from the above.

As many widely different embodiments of this invention can be made without departing from the spirit and scope thereof, it is to be understood that the invention is not to be limited except as defined by the claims.

What is claimed is:

1. A photographic element comprising a hydrophobic orientable polyester film base bearing on at least one surface a substratum composed of a mixture of 99 to 50 parts by weight of a polyester of a glycol and terephthalic acid which has a molecular weight in excess of 5,000 and is soluble to the extent of at least /2% by weight in trichlorethylene and 1 to 50 parts by Weight of an organic compound taken from the group consisting of organic polyisocyanates and organic polyisothiocyanates and having a water-permeable colloid layer in contact with said substratum.

2. A photographic element as set forth in claim 1 wherem said water-permeable layer contains light-sensitive silver halides.

3. A photographic film comprising a hydrophobic orientable polyester film base bearing on at least one surface a substratum composed of a mixture of 99 to 50 parts by weight of a polyester of a glycol and terephthalic acid which has a molecular weight in excess of 5,000 and is soluble to the extent of at least /2% by weight in trichlorethylene and 1 to 50 parts by weight of an organic compound taken from the group consisting of organic polyisocyanates and organic polyisothiocyanates, having a water-permeable colloid layer on said substratum and having a water-permeable colloid silver halide emulsion layer on said latter layer.

4. A photographic film comprising a polyethylene terephthalate film base bearing on at least one surface a substratum composed of a mixture of 99 to 50 parts by weight of a polyester of a glycol and terephthalic acid which has a molecular weight in excess of 5,000 and is soluble to the extent of at least /2% by weight in trichlorethylene and 1 to 50 parts by weight of an organic compound taken from the group consisting of organic polyisocyanates and organic polyisothiocyanates and having a water-permeable colloid layer in contact with said substratum.

5. A film element as set forth in claim 3 wherein said compound is a polymethyleneisocyanate of 2 to 12 carbon atoms.

6. An element as set forth in claim 3 wherein said compound is a diisocyanate of an aromatic hydrocarbon.

7. An element as set forth in claim 6 wherein said diisocyanate is methylene bis(4-phenylisocyanate).

8. An element as set forth in claim 6 wherein said diisocyanate is toluene-2,4-diisocyanate.

9. A photographic element comprising a hydrophobic orientable polyester film base bearing on at least one surface a substratum composed of a mixture of 99 .to 50 parts by weight of a polyester of a glycol and terephthalic acid which has a molecular weight in excess of 5,000 and is soluble to the extent of at least /2% by Weight in trichlorethylene and 1 to 50 parts by weight of an organic compound taken from the group consisting of organic polyisocyanates and organic polyisothiocyanates and having a gelatin silver halide emulsion layer in contact with said substratum.

10. A photographic film comprising a polyethylene terephthalate film base bearing on one surface a substratum composed of a mixture of 99 to 50 parts by weight of a polyester of a glycol and terephthalic acid which has a molecular weight in excess of 5,000 and is soluble to the extent of at least /z% by weight in trichlorethylene and 1 to 50 parts by weight of an organic compound taken from the group consisting of organic polyisocyanates and organic polyisothiocyanates, a gelatin layer on said substratum and a gelatino silver halide emulsion layer on said gelatin layer.

11. A process which comprises applying to at least one surface of a hydrophobic orientable polyester film base, a film-forming mixture in a solvent containing 99 to 50 parts by weight of a polyester of a glycol and terephthalic acid which has a molecular weight in excess of 5,000 and is soluble to the extent of at least /2% by weight in trichlorethylene and 1 to 50 parts by Weight of an organic compound taken from the group consisting of organic polyisocyanates and organic polyisothiocyanates, drying the resulting layer and coating thereon a Water-permeable colloid layer.

12. A process as set forth in claim 11 wherein the drying is carried out at temperatures from C. to C.

13. A method as set forth in claim 11 wherein said water-permeable colloid contains light-sensitive silver halides.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A PHOTOGRAPHIC ELEMENT COMPRISING A HYDROPHOBIC ORIENTABLE POLYESTER FILM BASE BEARING ON AT LEAST ONE SURFACE A SUBSTRATUM COMPOSED OF A MIXTURE OF 99 TO 50 PARTS BY WEIGHT OF A POLYESTER OF A GLYCOL AND TEREPHTHALIC ACID WHICH HAS A MOLECULAR WEIGHT IN EXCESS OF 5,000 AND IS SOLUBLE TO THE EXTENT OF AT LEAST 1/2% BY WEIGHT IN TRICHLORETHYLENE AND 1 TO 50 PARTS BY WEIGHT OF AN ORGANIC COMPOUND TAKEN FROM THE GROUP CONSISTING OF ORGANIC POLYISOCYANATES AND ORGANIC POLYISOTHIOCYANATES AND HAVING A WATER-PERMEABLE COLLID LAYER IN CONTACT WITH SAID SUBSTRATUM. 